A remarkable and unexpected interaction effect between high frequency ultrasound energy and bioelectrically excitable tissue will be employed to the development of a line of advanced microstimulators for medical neurogenic applications An excised nerve preparation as well as hippocampal tissue slices of the rat brain will be used as physiologic models for further study of the ultrasound interactions with natural and applied bioelectric currents. The limits of ultrasound effectiveness in this application, some preliminary evaluations of its safety, and exploration of different methods of applying the ultrasound to neural tissue will be conducted. Micro-sized ultrasound transducers will be fabricated using photographic techniques and submillimeter diameter lithium niobate crystals in an effort to characterize the ultimate limits of its miniaturization and potential for implantation. This work will serve to underpin a new approach to neuro-electric stimulation that uses ultrasound energy to substantially reduce the current levels required to stimulate nerves in the body and possibly open up new applications of neural stimulation. PROPOSED COMMERCIAL APPLICATIONS: Ultrasonic neural stimulators would improve the effectiveness of therapeutic electrical stimulation which is currently a multibillion dollar market. The apparent advantages of ultrasound combined with lower levels of electrical stimulation suggest medical applications of the spinal cord, peripheral nerve and brain. This market is currently served with conventional electrostimulators by large medical device companies like Medtronic, Guidant, and others.